The present invention is based on Japanese Patent Application No. 2001-9382, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a grounding method of a braided wire for electromagnetic wave shielding by folding the braided wire over and covering the terminal end of the shielded wire with a cylindrical shield terminal as well as securely caulking around the circumference of the shielded wire in order to ensure adequate electrical conductivity. In particular, the present invention relates to a shielded wire terminal end structure that provides stable electrical conductivity.
2. Related Art
Generally, various terminal end structures are employed to ground a shielded wire for which electromagnetic wave braided shielding is employed. Conventionally, the method shown in FIGS. 4 to 6 is employed to stabilize the conduct of electricity.
As is shown in FIG. 4, for a grounding connection, a terminal process is performed for a shielded wire 1. That is, for the shielded wire 1, a conductive member 2 is surrounded by an insulating member 3 covered by a braided shield 4, which is woven to form a mesh-like structure of intertwined conductive lines, over which a sheath 5 is fitted. The thus arranged S shielded wire 1 is connected to a box as is shown in FIG. 5. That is, first, the braided shield 4 is exposed by peeling the sheath 5 off the terminal end of the shielded wire 1, then, portions of the exposed distal end of the braided shield 4 and the insulating member 3 are peeled off to expose the conductive member 2.
A shield terminal 6 is then attached to the thus prepared shielded wire 1, and the braided shield 4 of the shielded wire 1 is connected to the shield terminal 6. As is shown in FIG. 6, formed at one end on opposite sides of a rectangularly shaped plate 7 of the shield terminal 6 are brackets 9 and 11 in which are respectively provided holes 8 and 10, through which a screw can be inserted to secure the bracket 9 to the seat (not shown) of a box. Grounding of the holes 8 and 10 can also be accomplished by the connection to them of a ground line (not shown).
Finally, to form the shield terminal 6, the shielded wire 1 is positioned on the plate member 7, between the brackets 9 and 11, so that one end of the shield terminal 6 corresponds to the distal end of the sheath 5. Then, the shielded wire 1 is enclosed in the plate 7 by raising the brackets 9 and 11 at both side ends, so that the end of the plate 7 of the shield terminal 6 abuts upon the shielded wire 1. At this time, the inner faces of the brackets 9 and 11 are aligned, and thereafter, the braided shield 4 of the shielded wire 1 is folded back around the outer wall of the shield terminal 6. A caulking ring 12 is then fitted over the folded, braided shield 4, and is caulked to press the braided shield 4 against the outer wall of the shield terminal 6.
After the attachment of the shield terminal 6 to the shielded wire 1 has been effected, the shielded wire 1 is secured to the seat on the box by inserting a screw through the holes 8 and 10 of the shield terminal 6 and rotating the screw to engage a threaded hole in the box or by inserting a grounding line (not shown) through the holes 8 and 10 of the shield terminal 6. In this manner, an external electric connection is established for the braided shield 4 of the shielded wire 1.
When the shielded wire 1 is enclosed and the inner face of the bracket 9 of the shield terminal 6 is aligned with the inner face of the bracket 11, a slit 14 is defined at the portion whereat the side end of the plate 7 of the shield terminal 6 is abutted. This slit 14 is narrowed when the braided shield 4 of the shielded wire 1 is folded over the outer wall of the shield terminal 6 and a caulking ring 12 is fitted over the folded braided shield 4 and is securely caulked, as is shown in FIG. 7. Then, one part of the plate 7 at the end face covers the other part, and thus, an overlapped portion 13 is formed. At this time, since the brackets 9 and 11 are extended perpendicular to the plate 7, i.e., in the horizontal direction, the slit 14 is positioned at the vertex of the caulked shape.
In addition, since the braided shield 4 of the shielded wire 1 is folded over the outer face of the shield terminal 6, and the caulking ring 12 is fitted over the braided shield 4 and then caulked, the pressure is applied only to one end of the plate 7 of the shield terminal 6, and the gap is removed only on the side nearest the caulking ring 12. As a result, as is shown in FIG. 10, as the caulking ring 12 is caulked, the overlapped portion 13 is formed at the other end of the plate 7.
Therefore, the shape of the caulked portion is such that it is weakened, and may be vulnerable to the application of an external load (because only one side of the caulked portion is pressed down). And when the overlapped portion 13 is formed, whereat one side of the end covers the other, the slit 14 is concentrated at the portion whereat the braided shield 4 of the shielded wire 1 is folded for insertion, and at this portion, the braided shield 4 may be severed. In addition, if the slit 14 is defined when the inner faces of the bracket 9 and the bracket 11 of the shield terminal 6 are brought together, and the gap between the sides at that end of the plate 7 of the shield terminal 6 is not reduced, the pressure produced by the caulking will not be distributed across the braided shield 4 of the shielded wire 1, and a stable caulked portion will not be obtained.
It is, therefore, an objective of the present invention to provide a terminal end structure for a shielded wire cable that ensures that after caulking no slit remains between the side end faces of the shield terminal, and that one side end face of the shield terminal does not ride up over.
To achieve the above objective, according to a first aspect of the invention, provided is a terminal end structure wherein a shielded wire is enclosed therein comprising: a shield terminal having a bracket for grounding at a side thereof, the shield terminal being formed in a cylindrical shape from a plate; a braided shield being exposed from the shielded wire, and folded over an outer wall of the shield terminal; a caulking ring fitted over the braided shield and securely retaining the outer wall of the shield terminal; and wherein a portion whereat both side ends of the shield terminal are aligned has a non-linear shape.
Preferably the portion whereat both side ends of the shield terminal are aligned may include at least one tongue formed in one of the side ends of the shield terminal, and opposing to at least one indented portion formed in another of the side ends of the shield terminal.
According to the first aspect of the invention, with this arrangement, after caulking has been performed, no slit is defined between the end faces of the shield terminal, so that one side end face of the shield terminal can be prevented from riding up and over.
Further, to achieve the object of the invention, according to a second aspect of the terminal end structure for the shielded wire, wherein the tongue and the indented portion are formed in each of the side end of the shield terminal, lengths of the tongues formed in both side ends are substantially the same.
According to the second aspect, with this arrangement, after caulking has been performed, no slit is defined between the side end faces of the shield terminal, so that one side end face of the shield terminal can be prevented from riding up over.
In addition, to achieve the objective of the invention, according to a third aspect of the terminal end structure for the shielded wire, wherein the caulking ring is caulked over the braided shield folded, so that the caulking ring is securely pressed against the outer wall of the shield terminal.
According to the third aspect, with this arrangement, after caulking has been performed, no slit is defined between the end faces of the shield terminal, so that one end face of the shield terminal can be prevented from riding up over.